From: "Jeff Janes" <jeff.janes@xxxxxxxxx>Hi Jeff:
To: "Ray Cote" <rgacote@xxxxxxxxxxxxxxxxxxxxxxxx>
Cc: pgsql-general@xxxxxxxxxxxxxx
Sent: Thursday, June 6, 2013 5:41:00 PM
Subject: Re: [GENERAL] Database performs massive reads when I'm doing writes.On Thu, Jun 6, 2013 at 2:12 PM, Ray Cote <rgacote@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:It is Postmaster itself:
11068 - 315.9M 136K 0K 85% postmaster
11000 - 56808K 8K 0K 15% postmaster
11003 - 0K 80K 0K 0% postmaster
11004 - 0K 24K 0K 0% postmaster
11067 - 0K 0K 0K 0% load_rets.py
The above are the atop lines for just postmaster. This is a 10s snapshot so you can see lots of read activity.
The load_rets.py task is the Python script loading the database.The postmaster has many children, each of which is responsible for something different. If you display the full command line rather than just the abbreviated one, it will give you more info on exactly which child is using the disk, for example:PID DSK COMMAND-LINE3950 16% postgres: jjanes jjanes [local] UPDATE2978 0% postgres: checkpointer process2982 0% postgres: stats collector processCheers,Jeff
I can see that now after pressing c in disk display mode:
19007 - D 86% postgres: postgres petersons 127.0.0.1(59702) UPDATE
11003 - S 12% postgres: writer process
11004 - S 2% postgres: wal writer process
This is how it looks when running properly (doing a big update at the moment).
Thanks for the lead. Learning much about atop today.
--Ray
--
Ray Cote, President Appropriate Solutions, Inc.
We Build Software
www.AppropriateSolutions.com 603.924.6079
We Build Software
www.AppropriateSolutions.com 603.924.6079
